Because cats were first and I have much more interesting conversations with them. For example, my friend Elizabeth's dog Clark simply states "I'm a dog" repeatedly, while @JBoogaloo‌ 's cat is forming the Meow Reich as new leader of SS in the absence of Kitler ... who I found on an adoption site recently.

Dogs are essentially manufactured pets, we breed them to be what we want them to be. Everything about them is the way it is because we wanted it that way, so we selected for it over many generations. Everything from their cuteness to their loyalty is manufactured by man. Their existence is man's most obvious triumph over nature, but also his saddest creation. Like a lonely boy who makes a friend for himself out of robot parts, man was sad that none of the animals liked him, so he made one that lived only to please him.

Cats, however, choose to live near us for their own benefit. The housecat is still shaped basically like the wild cats of their ancestry, and while there have been a few breeds of cat which were created on purpose by man, they are mostly aesthetic (shorter fur, bobbed tails, big ears, etc.) not behavioral. Most of the evolution that brings cats into symbiosis with man occurred more naturally as man and cat lived side-by-side. The affection they show us is just as much benefit to them as it is to us, they don't exist to please, they chose to live in company.

Dog may be man's 'best' friend, and dog may love man with every fiber of his smashing, waggling tail, but it's a hollow, crafted love, which we carved out selfishly for ourselves. Cat is a real friend to man, one who loves him for the right reasons, and gives that love freely and naturally, if perhaps, less worshipfully.